TGF-beta in Mammary Development and Tumorigenesis

基质-上皮相互作用在乳腺发育和肿瘤发生中的重要性是众所周知的。 确立了习这些相互作用可能涉及多种生长因子的自分泌和旁分泌作用， 包括TGF-13家族的成员，其在基质和上皮中表达。我们有 先前证明，显性负性II型TGF-1受体构建体（DNIIR）的表达， 使用金属硫蛋白（MT）启动子的乳腺基质导致侧向分支增加。电流 有证据表明DNIIR仅引起TGF-6信号传导的部分阻断。为了完成 敲除乳腺基质细胞中的II型TGF-β 1受体基因（Tgfbr 2），我们将FSP 1-Cre 小鼠与Tgfbr 2（Tgfbr 2/Tgfbr 2）小鼠。FSP 1（成纤维细胞特异性蛋白-I）在间质中表达。 成纤维细胞如初步研究所示，这些小鼠的表型与观察到的不同 MT-DNIIR小鼠中基质细胞中TGF-β 1信号传导部分消失。完全清除 间质细胞中的tgfbr 2，乳腺脂肪细胞丢失，间质细胞明显增多， 导管分支减少，上皮细胞发育不良。FSP 1-Cre和杂合子动物 floxed Tgfbr 2 [Tgfbr 2（E2/wt）]使它们在基质细胞中对Tgfbr 2单倍不足， 乳腺发育，但泌乳后退化。因此，我们有一个独特的模式， 研究TGF-13信号在乳腺发育和肿瘤发生中的作用。 基于这些信息，我们提出了以下假设：（1）基质中的TGF-13信号转导是 对乳腺的正常发育至关重要，并在乳腺癌的侵袭和转移中起作用。 癌细胞的潜能。(2)Tgfbr 2的基质单倍不足导致不完全消退 并改变了乳腺肿瘤的侵袭和转移能力， 表达的癌基因。本研究的具体目的是：1.表征 FSP 1-Cre：Tgfbr 2（FSP 2/FSP 2）小鼠Cre表达模式、重组和表型。2. Tgfbr 2单倍缺陷小鼠Cre基因表达谱、重组及表型分析 在基质中，FSP 1-Cre：Tgfbr 2（Tgfbr 2/wt）小鼠。3. Tgfbr 2缺失基质细胞的表征和 测定它们对癌细胞侵袭和转移的影响。

The importance of stromal-epithelial interactions in mammary gland development and tumorigenesis is well established. These interactions likely involve autocrine and paracrine action of multiple growth factors, including members of the TGF-13 family, which are expressed in both stroma and epithelium. We have previously demonstrated that expression of a dominant-negative type II TGF-I_ receptor construct (DNIIR) in mammary stroma using a metallothionein (MT) promoter results in increased lateral branching. Current evidence indicates that DNIIR causes only partial blockage of TGF-6 signaling. To accomplish complete knock-out of the type II TGF-I_ receptor gene (Tgfbr2) in mammary stromal cells we have crossed FSP1-Cre mice with the Tgfbr2(floxE2/floxE2) mice. FSP1 (fibroblast-specific protein-I) is expressed in stromal fibroblasts. As shown under Preliminary Studies, these mice have a phenotype different from that observed with partial abrogation of TGF-I_ signaling in stromal cells in the MT-DNIIR mice. With complete knock-out of Tgfbr2 in stromal cells there was loss of mammary fat cells with a markedly hypercellular stroma and decreased ductal branching with hypoplastic epithelial cells. Animals with FSP1-Cre and heterozygous floxed Tgfbr2 [Tgfbr2(floxE2/wt)] making them haploinsufficient for Tgfbr2 in stromal cells have normal mammary gland development, but defective regression following lactation. Thus, we have a unique model for studying the role of TGF-13 signaling in stromal cells on mammary gland development and tumorigenesis. Based on this information, we have formulated the following hypotheses: (1) TGF-13 signaling in stroma is essential for normal development of the mammary gland and plays a role in the invasive and metastatic potential of carcinoma cells. (2) Stromal haploinsufficiency of Tgfbr2 leads to incomplete regression following lactation and alters the invasion and metastatic capabilities of mammary tumors induced by co- expressed oncogenes. The Specific Aims are proposed to test these hypotheses are: 1. Characterization of Cre expression pattern, recombination and phenotype of FSP1-Cre:Tgfbr2(floxE2/floxE2) mice. 2. Characterization of Cre expression pattern, recombination and phenotype of mice haploinsufficient for Tgfbr2 in stroma, FSP1-Cre:Tgfbr2(floxE2/wt) mice. 3. Characterization of Tgfbr2 null stromal cells and determination of their effect on invasion and metastasis of carcinoma cells.